- المجال: Mining
- Number of terms: 33118
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The U.S. Bureau of Mines (USBM) was the primary United States Government agency conducting scientific research and disseminating information on the extraction, processing, use, and conservation of mineral resources.
Founded on May 16, 1910, through the Organic Act (Public Law 179), USBM's missions ...
A laminated, metamorphosed oxide-facies iron formation in which (1) the original chert or jasper bands have been recrystallized into megascopically distinguishable grains of quartz and (2) the iron is present as thin layers of hematite, magnetite, or martite (Dorr & Barbosa, 1963). The term was originally applied in Itabira, Brazil, to a high-grade, massive specular-hematite ore (66% iron) associated with a schistose rock composed of granular quartz and scaly hematite. The term is now widely used outside Brazil. Compare: jacutinga; canga.
Industry:Mining
A lamp that is charged with calcium carbide and water and burns the acetylene generated.
Industry:Mining
A lamp that is charged with calcium carbide and water and burns the acetylene generated.
Industry:Mining
A lamp, the flame of which is so protected that it will not immediately ignite combustible gases. The original flame safety lamp was developed by Sir Humphrey Davy in 1815 and there are several varieties. The flame is generally surrounded by a cylindrical covering of wire gauze. An explosive or flammable mixture of gas entering the lamp will be ignited by the flame, but the flame of combustion will not pass through the cool gauze and ignite the gas outside the lamp. The illuminating power of these lamps is slightly more than 1 cd, and they will burn for an entire shift with one filling. Each lamp is generally provided with a relighting device, and with a magnetic lock to prevent the lamp from being opened in the mine. The chief disadvantage of this lamp is 1218 its low illuminating power.
Industry:Mining
A lamprophyre chiefly composed of biotite or phlogopite and melilite as essential minerals, commonly with olivine, calcite, and clinopyroxene. Perovskite, apatite, nepheline, and garnet may be present. Its name (Rosenbusch, 1887) is derived from Alnoe, Sweden. Also spelled allnoeite; alnoeite.
Industry:Mining
A lamprophyre composed of hornblende phenocrysts in a groundmass of alkali feldspar and hornblende. Clinopyroxene, olivine, and plagioclase feldspar also may be present. Vogesite contains less biotite than minette. The name, given by Rosenbusch in 1887, is for the Vosges Mountains, France.
Industry:Mining
A lamprophyre containing biotite and plagioclase (usually oligoclase or andesine), with or without clinopyroxene and olivine. Defined by Delesse in 1851; named for the village of Kersanton, France.
Industry:Mining
A lamprophyre containing phenocrysts of olivine, clinopyroxene, and typically biotite or amphibole (barkevikite), in a groundmass of glass or analcime, often highly altered. Nepheline or leucite may be present. Its name is derived from Serra de Monchique, Portugal.
Industry:Mining
A lamprophyre, similar in composition to nepheline diorite, being composed essentially of plagioclase (usually labradorite) and brown hornblende (usually barkevikite).
Industry:Mining
A landform developed in regions of gently inclined strata, particularly where hard and soft strata are interbedded. A long, gentle sloping surface that parallels the dip of the bedding planes of the strata below ground.
Industry:Mining
